1. Field of the Invention
This invention relates to a method and machine for batching coloring agents into paints and varnishes by volume, and to a machine which will dispense said coloring agents accurately.
2. Description of the Prior Art
The prior art embraces machines which are manually operated, semiautomatic or fully automatic plunger types featuring a set of vertically disposed dispensers with respective cylinders, equal in number to the colors to be batched into the medium. Each cylinder contains and supplies a single color. The accuracy of such machines, particularly questionable in the case of manual operation because of human error, improves with automation. Nevertheless, the hydraulic cylinders used to control reciprocating motion of the plungers in such machines are expensive and include additional drawbacks. There is always considerable downtime due to the return stroke of the plunger which refills the dispenser cylinder with coloring agent. In addition, such machines are characterized by low efficiency, especially in the conversion of electrical energy to mechanical energy.
The prior art also contains automated machines which utilize positive displacement pumps and solenoid valves with individual direct current motors and couplers, one for each color to be dispensed. Such machines recirculate excess color via a closed circuit. Although this machine is more desirable than the above described machines, this type is also economically inefficient because of the need for a large number of direct current motors, which require setting, attendant servicing, and the like.
When automated, machines in the prior art also become noticeably large and cumbersome.
There is an every increasing requirement for a greater number of shades in each color manufactured and this ever increasing need accentuates the problem of batching accurately. The prior art machines tend to be accurate only on an order of 5 to 10%. This accuracy does not permit obtaining all shades currently demanded and mixes often do not correspond to the actual shade called for and shades themselves become confused with each other.